In the 1950s and 1960s, basic science and applied research studies were taking place with hallucinogens, offering hints that they might be of value in psychotherapy, addiction treatment, and creativity enhancement, and suggestions that the hallucinogens can occasion mystical-type experiences. Laws enacted in response to excesses of the “psychedelic 1960s” stopped almost all that work, leaving some promising threads dangling. Despite ongoing illicit and licit use, remarkably little is known, from the standpoint of modern psychopharmacology research, about the acute and long-term effects of the hallucinogens. Our study is among the first to re-open this field. Since the Hopkins psilocybin work began, researchers at other major universities, such as UCLA, the University of Arizona, and Harvard, have begun planning or are carrying out hallucinogen research.

Q 2: Do you have any sign that the same brain “machinery” affected by psilocybin is identical to what people experience in spiritual epiphanies that occur without drugs?

That work hasn’t been done yet, though there is good reason to believe that similar mechanisms are at work during profound religious experiences, however they might be occasioned (for example, by fasting, meditation, controlled breathing, sleep deprivation, near death experiences, infectious disease states, or psychoactive substances such as psilocybin). The neurology of religious experience, newly termed neurotheology, is drawing interest as a new frontier of study.

Q 3: Is this God in a pill? Does it render God or “revelation” irrelevant?

The scientific method works with what can be observed in the physical realm, using tools such as atomic particle detectors, medical imaging devices, people’s responses to psychological tests, interviews, and behavioral observations. We are attempting neither to validate nor to invalidate the truth of claims that some people have made about metaphysical realities as a consequence of their psilocybin experiences (or as a consequence of their meditation, fasting, or prayer experiences)—that’s beyond our purview as scientists. It is within the purview of science to study the changes in mood, values, view of self, and behaviors that may follow such experiences.

Of course it would be a profound mistake to confuse the experience of something for the thing itself. We are not aware of study participants who felt their psilocybin experience devalued their own religious traditions; interviews suggested the opposite was more usually the case.

Q 4: Are you trying to find a short cut to the spiritual journey that some people pursue for years?

Our focus in this research was to study the effects of psilocybin using the methods of modern psychopharmacology. It’s true that “transformative” changes in values, self-perception, and behaviors have been reported across cultures and eras as a consequence of mystical-type experience. This bears investigation.

Q 5: Should religions feel threatened by this work?

I can’t see why.

The psychologist Walter Clark, in his 1958 book “The Psychology of Religion”, had this to say: “There is no more difficult word to define than ‘religion’… With full recognition that we are on ground where the experts disagree… we will venture our own definition. It is our feeling that religion can be most characteristically described as the inner experience of the individual when he senses a Beyond, especially as evidenced by the effect of this experience on his behavior when he actively attempts to harmonize his life with the Beyond.”

Many of the volunteers in our study reported, in one way or another, a direct, personal experience of the “Beyond.” Far from being threatened, the only thing we can imagine being of greater interest to religions is whether people live more wholesome, compassionate, and equanimous lives in consequence of such experiences.

Q 6: Why did you use volunteers who have active spiritual practices? Didn’t that help assure the results you got?

Psilocybin and similar compounds have been reported to sometimes bring about experiences called spiritual, religious, mystical, visionary, revelatory, etc. Such experiences may be difficult psychologically and emotionally. We felt that volunteers who had some engagement with prayer, meditation, churchgoing, or similar activities would be better equipped to understand and consolidate any mystical-type experiences they might have in the study.

Q 7: Aren’t hallucinogens dangerous? How can you give them to human volunteers?

No mind-affecting drug is absolutely safe. But the risks of the hallucinogens can be managed in appropriate research settings.

Unlike drugs of abuse such as alcohol and cocaine, the classic hallucinogens are not known to be physically toxic and they are virtually non-addictive, so those are not concerns.

The primary effect of psilocybin, in medium to large doses, is strong alteration of consciousness. It is possible that such experiences can trigger latent schizophrenia in susceptible individuals. Thus in our study we disqualified potential volunteers whose personal or family psychiatric histories indicate that they may be at increased risk of that disorder.

Our study confirms that some individuals, during some or all of the hours of the drug’s action, may experience paranoia, extreme anxiety, or other unpleasant psychological effects. It is not difficult to imagine such stresses leading to dangerous or inappropriate behaviors, which may constitute the substance’s most prominent risk. We managed that in our study through a short course of psychological preparation and through careful and interpersonally sensitive monitoring of each drug session. The monitors were trained to provide reassurance (e.g., supportive words or gentle touch to a hand) if needed.

Q 8: What kind of substance is psilocybin?

Psilocybin is one of a class of compounds whose primary activity is known to be on 5-HT-2a/c serotonin receptors. Their effects include changes in perception and cognition. In the pharmacology literature, this class of drugs is called “hallucinogens,” though they rarely cause “hallucinations” in the sense of seeing or hearing things that are not there. Within other academic fields, the term ‘entheogen,’ roughly meaning “spirit-facilitating,” is coming into prominence for this class of substances.

Q 9: Studies at Hopkins have shown the potential for brain damage from MDMA (“ecstasy”). How do you know psilocybin doesn’t have the same risk?

Some studies have shown that MDMA can damage certain nerve cells. There is no experimental or clinical evidence in animals or humans that psilocybin, even in very high doses, is similarly neurotoxic. Enough research has been done with psilocybin, starting in the 1950s, that we can be reasonably confident that it is not physically toxic in doses humans ordinarily use. This is consistent with the fact that psilocybin-containing mushrooms have not, in millennia of use, acquired a reputation of being physically harmful. Traditions that use psilocybin mushrooms do, however, caution about psychological and spiritual risks of using them haphazardly.

Dr. Kleber wrote, “The positive findings of the study cannot help but raise concern in some that it will lead to increased experimenting with these substances by youth in the kind of uncontrolled and unmonitored fashion that produced casualties over the past three decades…

“Any study reporting a positive or useful effect of a drug of abuse raises these same concerns. In this Internet age, however, where youth are deluged with glowing personal reports in chat rooms and web sites as well as detailed information about the various agents and how to use them, it is less likely that a scientific study would move the needle much.

“Psychedelic drug use has remained in a relatively constant range over the past three decades as various fads have come and gone and enthusiastic personal accounts are balanced by negative reports about casualties.

Discovering how these mystical and altered consciousness states arise in the brain could have major therapeutic possibilities, e.g., treatment of intolerable pain, treatment of refractory depression, amelioration of the pain and suffering of the terminally ill, to name but a few, as well as the… needed improvement in treatment of substance abuse… so that it would be scientifically shortsighted not to pursue them.”

[…] Huston Smith, holder of 12 honorary degrees, is one of the great authorities on comparative religion. His book “The World’s Religions” has for forty years been the most widely used textbook on its subject, and in 1996 he was the focus of a five part Bill MoyersPBS program, “The Wisdom of Faith with Huston Smith.” […]

Commenting on the Griffiths et al. study, Smith said:

“Mystical experience seems to be as old as humankind, forming the core of many if not all of the great religious traditions. Some ancient cultures, such as classical Greece, and some contemporary small-scale cultures, have made use of psychoactive plants and chemicals to occasion such experiences. But this is the first scientific demonstration in 40 years, and the most rigorous ever, that profound mystical states can be produced safely in the laboratory. The potential is great.”

Smith also issued a caution and suggested that further research on the topic include social as well as neurological variables: “In the end, it’s altered traits, not altered states, that matter. ‘By their fruits shall ye know them.’ It’s good to learn that volunteers having even this limited experience had lasting benefits. But human history suggests that without a social vessel to hold the wine of revelation, it tends to dribble away. In most cases, even the most extraordinary experiences provide lasting benefits to those who undergo them and people around them only if they become the basis of ongoing work. That’s the next research question, it seems to me: What conditions of community and practice best help people to hold on to what comes to them in those moments of revelation, converting it into abiding light in their own lives?”